1. Field of the Invention
The present invention relates generally to a slide fastener, and more particularly to a continuous row of fastener elements of coiled or meander configuration made of a plastic monofilament and used for manufacture of slide fasteners.
2. Description of the Prior Art
Heretofore, some continuous fastener elements of the type described above have their whole coupling heads merely flattened by a suitable means such as stamping rollers and others have their whole coupling heads similarly flattened and furthermore have the thus flattened coupling heads convexed over their entire front faces.
When opposed fastener element rows of the conventional types pass through a Y-shaped guide channel of a slider for opening and closing a slide fastener, mating coupling heads of the opposed fastener element rows make surface-to-surface contact with each other within the Y-shaped guide channel of the slider, which contact causes the reciprocation of the slider sluggish. Furthermore, since the coupling heads are convexed over their entire front faces, the mating coupling heads of the opposed fastener element rows in face-to-face contact with each other within the slider are inclined to slip over their convex front faces and displace out of coupling alignment with each other, so that the fastener elements are unstable to carry out coupling and uncoupling operation.